Swimming New Zealand have expressed their concern over reports that races will be scheduled late at the Rio 2016 Olympic Games to suit the American television market.

Website Swim Vortex has claimed that finals in the swimming event could start at 10pm in Brazil, which has raised concerns over possible minimal recovery time for the athletes.

"While we appreciate the importance of commercial considerations in the successful staging of an Olympics that should not impinge on the welfare of the athletes which must remain paramount," said Swimming New Zealand chief executive Christian Renford.

"If the report is factual, a 10pm start time would mean some swimmers may not get back to the village until 1am or 2am which is completely unreasonable.

"We will certainly make our feelings known to FINA and hope good sense would prevail if this report is to be believed."

The official schedules are yet to be finalised, but the Australian Olympic Committee have also expressed concern over the reports.